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Re: [Qemu-devel] [PATCH] seccomp: allow sched_setscheduler() with SCHED_
From: |
Eduardo Otubo |
Subject: |
Re: [Qemu-devel] [PATCH] seccomp: allow sched_setscheduler() with SCHED_IDLE policy |
Date: |
Wed, 11 Jul 2018 16:48:55 +0200 |
User-agent: |
Mutt/1.8.3+47 (5f034395e53d) (2017-05-23) |
On 10/07/2018 - 16:55:57, Marc-André Lureau wrote:
> Current and upcoming mesa releases rely on a shader disk cash. It uses
> a thread job queue with low priority, set with
> sched_setscheduler(SCHED_IDLE). However, that syscall is rejected by
> the "resourcecontrol" seccomp qemu filter.
>
> Since it should be safe to allow lowering thread priority, let's allow
> scheduling thread to idle policy.
>
> Related to:
> https://bugzilla.redhat.com/show_bug.cgi?id=1594456
>
> Signed-off-by: Marc-André Lureau <address@hidden>
> ---
> qemu-seccomp.c | 12 ++++++++++--
> 1 file changed, 10 insertions(+), 2 deletions(-)
>
> diff --git a/qemu-seccomp.c b/qemu-seccomp.c
> index 148e4c6f24..9cd8eb9499 100644
> --- a/qemu-seccomp.c
> +++ b/qemu-seccomp.c
> @@ -34,6 +34,12 @@
> struct QemuSeccompSyscall {
> int32_t num;
> uint8_t set;
> + uint8_t narg;
> + const struct scmp_arg_cmp *arg_cmp;
> +};
> +
> +const struct scmp_arg_cmp sched_setscheduler_arg[] = {
> + SCMP_A1(SCMP_CMP_NE, SCHED_IDLE)
> };
>
> static const struct QemuSeccompSyscall blacklist[] = {
> @@ -92,7 +98,8 @@ static const struct QemuSeccompSyscall blacklist[] = {
> { SCMP_SYS(setpriority), QEMU_SECCOMP_SET_RESOURCECTL },
> { SCMP_SYS(sched_setparam), QEMU_SECCOMP_SET_RESOURCECTL },
> { SCMP_SYS(sched_getparam), QEMU_SECCOMP_SET_RESOURCECTL },
> - { SCMP_SYS(sched_setscheduler), QEMU_SECCOMP_SET_RESOURCECTL },
> + { SCMP_SYS(sched_setscheduler), QEMU_SECCOMP_SET_RESOURCECTL,
> + ARRAY_SIZE(sched_setscheduler_arg), sched_setscheduler_arg },
> { SCMP_SYS(sched_getscheduler), QEMU_SECCOMP_SET_RESOURCECTL },
> { SCMP_SYS(sched_setaffinity), QEMU_SECCOMP_SET_RESOURCECTL },
> { SCMP_SYS(sched_getaffinity), QEMU_SECCOMP_SET_RESOURCECTL },
> @@ -118,7 +125,8 @@ static int seccomp_start(uint32_t seccomp_opts)
> continue;
> }
>
> - rc = seccomp_rule_add(ctx, SCMP_ACT_KILL, blacklist[i].num, 0);
> + rc = seccomp_rule_add_array(ctx, SCMP_ACT_KILL, blacklist[i].num,
> + blacklist[i].narg, blacklist[i].arg_cmp);
> if (rc < 0) {
> goto seccomp_return;
> }
> --
> 2.18.0.129.ge3331758f1
>
Acked-by: Eduardo Otubo <address@hidden>
Patch looks safe enough for me. If everyone else is OK with this I'll send a
pull-request tomorrow morning.
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